Mk2 GTI 8v repeat fan belt failures *EDITED*

[Superspecs]

Hi All,

I am currently having a nightmare with my fan/aux belts, the problem being they keep breaking/snapping/wearing at a ridiculous rate. I am not getting any squealing or anything to suggest the belt is too tight or too loose as far as I have noticed. I will just be driving along and the battery light will come on, I will stop, pop the bonnet and the belt will either be gone or hanging like a limp noodle doing absolutely nothing.

I don't know what to do other than keep replacing them but I am on my fourth in six months now.

Ive not got PAS or AC so the belt just runs the coolant pump, the alternator and a few slave pulleys.

****EDIT****

Last night I found my broken fan belt in the road just outside my house. On inspection it seems moderately worn all over apart from one point where it looks like it has worn more or less straight through to the canvas/thread base and then snapped.

To me it looks like something is causing it to wear and become slack eventually to the point where it is just hanging. Then since the crank pulley is still spinning it has worn it away until it has snapped.

Any ideas would be appreciated!

[VW BUSH]

If the pump is seizing then this can throw the belt or wear it through pretty quick.
If you have too much end float in the crank then this can make the belts jump off and wear.
If the pulleys are damaged or the rubber damper is goosed this can throw the belts.
Wrong belts used.
Pulley so worn the belts ride in the bottom of the v and not on the sides.
Too tight, need to be able to twist belt 90' (roughly)

[Mr Blue]

^ good call

Another one to check is how straight the belts run. The alternator has a spacer on the pulley from memory.

[Thom89]

All the above are good calls.
I've seen this problem a few times before over the years, and has been clutch/end float in the crankshaft related. Sit someone in the car with the engine running, and get them to depress the clutch pedal on and off at at regular intervals, your looking for a transverse movement on the CS pulley that could throw the belt off. I'm not sure what the tolerances are, but I would say that anything over 1 to 2mm should be investigated further.

Its probably the easiest thing to check, but unfortunately has the worst consequences!

Thom

[Superspecs]

All the above are good calls.
I've seen this problem a few times before over the years, and has been clutch/end float in the crankshaft related. Sit someone in the car with the engine running, and get them to depress the clutch pedal on and off at at regular intervals, your looking for a transverse movement on the CS pulley that could throw the belt off. I'm not sure what the tolerances are, but I would say that anything over 1 to 2mm should be investigated further.

Its probably the easiest thing to check, but unfortunately has the worst consequences!

Thom

Thanks for you advice. 

When you say "transverse" do you mean horizontal left/right movement if I am stood at the hood looking down at the CS pulley? Il check it tonight when I get home and update you.

[Superspecs]

If the pump is seizing then this can throw the belt or wear it through pretty quick.
If you have too much end float in the crank then this can make the belts jump off and wear.
If the pulleys are damaged or the rubber damper is goosed this can throw the belts.
Wrong belts used.
Pulley so worn the belts ride in the bottom of the v and not on the sides.
Too tight, need to be able to twist belt 90' (roughly)

Thanks for all the help. Just to check.. what do you mean by "goosed" 

[VW BUSH]

If the pump is seizing then this can throw the belt or wear it through pretty quick.
If you have too much end float in the crank then this can make the belts jump off and wear.
If the pulleys are damaged or the rubber damper is goosed this can throw the belts.
Wrong belts used.
Pulley so worn the belts ride in the bottom of the v and not on the sides.
Too tight, need to be able to twist belt 90' (roughly)

Thanks for all the help. Just to check.. what do you mean by "goosed" 

F*cked

The rubber falls out and the puuley moves about to much

[Superspecs]

Hi all,

So I think I have figured out what the problem was. On the alternator pulley there was a small patch of rust on the inside edge which was really quite rough that I believe was wearing through the belt. I took a bit of light sand paper to the rust to clean it up and now several weeks later seems fine.